Method of making patterned metal oxide films comprising a sol-gel of metal oxide and a photoactive compound

Abstract

A method of making patterned metal oxide films on microelectronic wafer substrates. They are prepared by making a sol-gel of a metal oxide in combination with an ultraviolet light sensitive photo-active compound. The sol-gel is applied to a silicon wafer substrate, and the wafer subjected to a predetermined pattern of ultraviolet light to cause the photo-active compound to respond to the ultraviolet light. The wafer is thereafter aqueous alkali metal hydroxide washed to wash away the portions of the metal alkoxide film which have been exposed to UV light.

What is claimed is: 
     
       1. A method of making patterned metal oxide films on microelectronic wafer substrates, comprising: (a) preparing a sol-gel of a metal oxide containing a small but effective amount of an ultraviolet light sensitive photo-active compound;   (b) applying the thin film of said sol-gel to a wafer substrate;   (c) drying the coated wafer;   (d) subjecting the wafer to a predetermined pattern of ultraviolet light to cause said photo-active compound to respond to said ultraviolet light;   (e) treating the wafer with aqueous alkali metal hydroxide to wash away those portions of the metal alkoxide film which has been exposed to ultraviolet light; and thereafter   (f) sintering the gel film to form a ceramic film.   
     
     
       2. A method of making patterned metal oxide films on microelectronic wafer substrates, comprising: (a) preparing a sol-gel of a metal oxide containing a small but effective amount of the ultraviolet light sensitive photo-active compound, which is 1-naphthalenesulfonic acid, 6-diazo-5, 6-dihydro-5-oxo-4-benzoyl-1,2,3 benzene triyl ester,   (b) applying the thin film of said sol-gel to a wafer substrate;   (c) drying the coated wafer;   (d) subjecting the wafer to a predetermined pattern of ultraviolet light to cause said photo-active compound to respond to said ultraviolet light;   (e) treating the wafer with aqueous alkali metal hydroxide to wash away those portions of the metal alkoxide film which has been exposed to ultraviolet light; and thereafter   (f) sintering the gel film to form ceramic film.   
     
     
       3. The method of claim 1 wherein the metal oxide is selected from the group consisting of oxides of aluminum, silicon, tungsten, titanium, vanadium, chromium, iron, cobalt, nickel, germanium, yttrium, zirconium, niobium, indium, tin, antimony, tantalum, and lead. 
     
     
       4. The method of claim 1 wherein the sol-gel includes an alcohol solvent. 
     
     
       5. The method of claim 3 wherein the alcohol solvent is selected from the group consisting of C 1  to C 3  alcohols and alkoxy alcohols. 
     
     
       6. The method of claim 1 wherein the photo-active compound is a diazoquinone. 
     
     
       7. The method of claim 1 wherein the weight ratio of photo-active compound to metal oxide is within the range of 1:1 to 4.5:1. 
     
     
       8. The method of claim 1 wherein an additional step comprises calcining the wafer to provide the patterned, ready-to-use wafer. 
     
     
       9. The method of claim 1 wherein the drying of the coated wafer is oven drying. 
     
     
       10. The method of claim 9 wherein the drying is at a temperature within the range of 80° C. to 120° C. 
     
     
       11. The method of claim 10 wherein the drying is at a temperature within the range of 90° C. to 110° C. 
     
     
       12. The method of claim 1 wherein the aqueous metal hydroxide has a concentration within the range of about 5% by weight to about 15% by weight. 
     
     
       13. The method of claim 12 wherein the weight basis concentration of the aqueous metal hydroxide is about 10%. 
     
     
       14. The method of claim 13 wherein the alkali metal hydroxide is potassium hydroxide. 
     
     
       15. The method of claim 12 wherein the wafer is treated with said aqueous hydroxide by dipping said wafer in said solution. 
     
     
       16. The method of claim 15 wherein said treating is for from about 10 seconds to about 30 seconds. 
     
     
       17. The method of claim 1 wherein said metal is titanium.